Pd/SAPO-34 passive NOx adsorbers: Stable Pd ion adsorption sites in six-member rings
Pd/SAPO-34 passive NOx adsorbers: Stable Pd ion adsorption sites in six-member rings
复制标题
Pd/SAPO-34 被动 NOx 吸附器：六元环中稳定的 Pd 离子吸附位点
DOI：
10.1088/2053-1591/abeb86
复制
发表时间：
2021
影响因子：
2.3
通讯作者：
Zhaoliang Zhang
中科院分区：
文献类型：
--
作者：
Nana Zhang;Ying Xin;Ruirui Li;Dongxu Han;Junxiu Jia;Qian Li;Jin Wang;Zhaoliang Zhang
具有chaabazite （CHA）拓扑结构的Pd/沸石是一种有效的被动NO x吸附剂（PNAs），有望在冷启动时从柴油尾气中去除NO x，以满足日益严格的排放法规。本文制备了不同制备方法和Pd含量的Pd/SAPO-34分子筛，并对NO进行了吸附。Pd/SAPO-34中分散良好的PdO - x簇、沸石八元环和六元环（8MRs和6MRs）上的Pd离子是NO的吸附位点，表明总Pd含量与NO的解吸量之间存在良好的线性关系。然而，在h2o存在下，由于孔径小的6MRs中Pd离子的迁移性有限，只有6MRs中的Pd离子是稳定的NO吸附位点并提供连续的NO吸附。这一新发现为合理设计高性能PNAs以消除柴油车冷启动过程中的nox排放指明了方向。
Pd/zeolites with chabazite (CHA) topology are effective passive NO x adsorbers (PNAs), which are promising for the removal of NO x from diesel exhausts during cold start to meet increasingly stringent emission regulations. In this work, Pd/SAPO-34 zeolites with different preparation methods and Pd contents were developed and exhibited high NO adsorption performance. Three Pd species in Pd/SAPO-34, including well-dispersed PdO x clusters, Pd ions in the eight-and six-member rings (8MRs and 6MRs) of zeolites, are NO adsorption sites in the absence of H 2 O in the feed, demonstrated by a good linear relationship between the total Pd contents and NO x desorption amounts. However, in the presence of H 2 O, only Pd ions in 6MRs are stable NO adsorption sites and provide the continuous NO adsorption, due to the limited mobility of the Pd ions in 6 MRs with small pore size. This new finding points out a definite direction for the rational design of high-performance PNAs to eliminate NO x during the cold start of diesel vehicles.